Expansible winding drum assembly

ABSTRACT

The specification and drawings disclose an expansible drum assembly particularly suited for use in rewinding metal strip. The disclosed device comprises a rotatably mounted center shaft having arcuate outer shells or segments carried thereon. The segments define the drum assembly&#39;&#39;s winding surface and each has a circumferential extent of less than 180*. One of the shells is pivotally connected to the shaft for arcuate movement in a generally radial direction. An actuating member extends longitudinally of the shaft between the shells. The actuating member has a surface which defines a continuation of the winding surface between the shells. Also, one surface on the actuating member is arranged to cam the pivotally mounted shell. Power means are provided for reciprocating the actuating member and radially. In the preferred embodiment, the power means comprise an expansible drum positioned between the actuating member and the shaft. Also disclosed is a strip clamp arrangement wherein the strip is clamped during outward movement of the actuating member.

United States Patent 1 Madachy I EXPANSIBLE WINDING-DRUM ASSEMBLY [75] Inventor: John F. Madachy, Mayfield Heights,

Ohio

[73] Assignee: Loopco Industries, Inc., Cleveland,

Ohio

22 Filed: Apr. 2, 1971 21] Appl. No.: 130,645

FOREIGN PATENTS 0R APPLICATIONS 509,247 10/1930 Germany' ..242/7s.3'

[ 1 June 11, 1974 Primary Examiner-George F. Mautz v Sharpe and The specification and drawings disclose an expansible drum assembly particularly suited for use in rewinding metal strip. The disclosed device comprises a rotatably mounted center shaft having arcuate outer shells or segments carried thereon. The segments define the drum assemblys winding surface and each has a circumferential extent of less than 180". One of the shells is pivotally connected to the shaft for arcuate movement in a generally radial direction. An actuating member extends longitudinally of the shaft between the shells. The actuating member has a surface which defines a continuation of the winding surface between the shells. Also, one surface on the actuating member is arranged to cam the pivotally mounted shell. Power the strip is clamped during outward movement of the actuating member.

11 Claims, 7 Drawing Figures PATENTEDJUH 1 1 m4 SHEET 10F 4 INVENTOR. JOHN F. MADACHY BY e fl m $44M AITORNEYS PATENTED m4 3815x339 8HEI 20$ 4 INV EN TOR. JOHN F MADACHY 4 5 8 Maw/W4 ATTORNEYS 3'815'839 munn m4 PATENTE SHEET 3 BF 4 INVENTOR. .52 JOHN F. MADACHY BY 4W, 5W 8 MuMollamZ ATTORNEYS PATENTEDJUM I ran SIEEI E 0F 4 I NVEN TOR. 7 JOHN E MADACHY BY 4 5W 8 Mal/0M ATTORNEYS EXPANSIBLE WINDING DRUM ASSEMBLY The Subject invention is directed toward the winding and reeling art and, more particularly, to an improved expansible winding mandrel or drum.

The invention is especially suited for use as a rewind drum for metal strip and will be described with particular reference thereto; however, as will be apparent, the invention is capable of broader application and could be used in many different winding, reeling and pay-out operations.

During the manufacture of metal strip, the strip must be wound into coils. Typically, a'n expansible and contractable drum having gripping jaws is used for the winding operation. With the drum in the expanded condition, the lead end of the strip is gripped in the jaws. As the drum is rotated, the strip is tightly wound into a coil on the outer surface of the drum. Thereafter, the drum is contracted and :the end of the strip released from the jaws. The coil is then removed by sliding it outwardly off the drum.

Many different types of expansible drums'have been used in the past. Generally, th drums have included multiple exterior segments carried on a rotatable cen-' ter shaft. Cams or wedges were mounted between the shaft and the segments so that when relative longitudinal movement was produced between the shaft and the segments, the segments moved radially. Many different types of actuators were used internally of the drums for producing the requiredmovements. Additionally, separate actuators were generally provided for moving the gripping jaws. v j

The most common feature of the prior drums was their large number of parts and general complexity which resulted from their design. Additionally, the sliding surfaces on the cams required much relatively precision machining. These factors combined to make the drums relatively expensive.

The subject invention provides an expansible drum assembly which is extremely simple in construction and reliable in operation. Drums formed in accordance with the invention basically require only two moving parts, thus greatly reducing manufacturing and maintenance costs. Further, no relative axial movement is required between the center shaft and the winding surface. In general, the invention contemplates a center shaft adapted to be cantileverly supported and having first and second arcuate outer shells or segments which define the winding surface and extend throughout a substantial portion of the length of the shaft. Each of the shells have a circumferential extent of less than 180 and, preferably, the first shell is formed integrally with or affixed to the shaft. The second shell is connected to the shaft along one of its longitudinal edges so that it can pivot radially. Means are provided to maintain the second shell continually biased in an inmember forms half 'a gripping jaw. The other half of the gripping jawis carried by the first segment and located so that during outward movement of the actuating member, the jaws engage. Thus, the gripping operation is produced simultaneously with the expansion and by the same power means.

The power means can be of many types; however, it preferably comprises a length of expansible hose positioned between the shaft and the actuating member. This provides an extremely simple and reliable power means. Merely by regulating the supply of pressure fluid to the hose, the expanding and gripping operations are controlled.v Other types of power means can be used. The specification discloses a second power ward direction. Also carried by the shaft and extending I means embodiment which vuses a manually driven screw member which acts against a slide bar pivotally connected to the actuating member to produce radial movement of the actuating member.

A more limited aspect of the invention contemplates that at least one-half the-gripping jaws will comprise a series of separate sections. Each of the sections is preferably biased toward the other jaw half-This allows the jaws to compensate for strip having varying thickness across its width.

As can be appreciated from the above, a primary object of the invention is the provision of an expansible drum of extremely simple design.

A further object of the invention is the provision of a drum of the general type described wherein only two moving parts are required to produce expansion and contraction.

Yet another object isthe provision of an expansible winding drum in which expansion takes place without any longitudinal relative movement.

Yet another object is the provision of a drum of the type described wherein a flexible hose serves as the power means.

The above and other objects and advantages will become apparent from the following description when read in conjunction with the accompanying drawings wherein:

FIG. I is a longitudinal sectional view through a winding drum formed in accordance with a preferred embodiment of the invention;

FIG. 2 is an end view of the FIG. 1 embodiment taken on line 2-2 of FIG. I;

FIG. 3 is a cross-sectional view taken on line 3-.3 of

FIG. 1;

FIG. 4 is an enlarged view of the lower right-hand corner of FIG. 1;

FIG. 5 is an enlarged view taken on line 55 of FIG.

FIG. 6 is a longitudinal crosssectional view similar to FIG. 1 but showing a modified form of actuating and power means; and,

FIG. 7 is a view taken on line 7-7 of FIG. 6.

Referring more particularly to FIGS. 1 and 2, the overall arrangement of the preferred embodiment of the expansible drum assembly 10 is shown as-including a main, generally cylindrical, center shaft 12 which is cantileverly mounted in or from a main support 14. The center shaft 12 is carried in suitable bearings (not shown) for driven rotation about its longitudinal center axis. The particular mechanisms provided for mounting and driving the mandrel assembly form no part of the present invention and any of the conventional arrangements could be used.

Carried on the shaft 12 for rotation therewith are a pair of first and second elongated shell or segment members 16 and 18 which cooperate to define the outer winding surface of the mandrel throughout a major portion of its total circumference. In the embodiment under consideration, each of the shells 16 and 18 extend substantially the length of the free end portion of the shaft 12 and have a circumferential extent of slightly less than 180. 7

Shell section 16 could be formed integrally with the center shaft 12 if desired, however, as best shown in FIGS. 2 and 3, it is preferably a separate element and includes a center sleeve or hub portion 20 which is positioned about shaft 12 andnon-rotatably connected thereto in any convenient manner such as through the use of keys 22. The winding surface defining portion 17 is connected to hub 20 at its lower-end and by spaced webs '24 which connect between the outer surface of hub 20 and the inner surface of portion 17 (see FIG. 1). As best shown in FIG. 1, the center hub 20 extends substantially the length of theshaft and is received against an enlarged diameter shoulder portion 26 formed at the inner end of the shaft. At the outer end, a circular r'etainer plate 28 engages a recess or shoulder formed in the free end of the hub. The retainer plate 28 is connected to the center shaft by a plurality of socket screws or the like 30 (see FIG. 2). This arrangement allows the entire outer portion of the drum to be readily removed from the center shaft 12, if desired.

As previously mentioned, winding drum assembly) is arranged so that its outer circumference can be selectively collapsed or contracted to permit ready withdrawal of a wound coil from the drum. For this reason, the shell 18 is mounted so that it can be moved in a generally radial direction relative to'the center axis of the shaft. For this reason, the shell section 18 is pivotally connected along its upper edge by a shaft 32 which extends longitudinally of the drum. As seen in FIGS. 1 and 3, a plurality of spaced, radially inwardly extending reinforcing ribs 30 having a tapered shape as best shown in FIG.'3, connect to the back of the shell. As best shown in FIG. 1, shaft 32 passes through aligned openings formed in each of the ribs 30 and the web sections 24. Set screws 36 pass through web sections 24 to engage the shaft and prevent its rotation. Openings 38, however, are sized so as to closely receive the shaft 32 while permitting free rotation so that oscillation of the shell section 18 is possible. Suitable collars 40 are connected at each end of the shaft to hold the shell section 18 properly located. As can be appreciated, the mounting arrangement for shell section 18 allows it to oscillate about the shaft 32 so that it can be moved from the expanding position shown in FIG. 2 to a collapsed or contracted position as shown in FIG. 3. It is important to note that each of the sections 16 and 18 have a circumferential extent of less than 180. This allows the effective winding diameter of the shell to be reduced for ready removal of a wound coil.

As is apparent, means must be provided for selectively actuating the shell section 18. Additionally, means are generally required for gripping the lead end of a metal strip and-holding it, particularly during the start of a winding operation. In the subject invention, the means for controlling drum expansion and gripping the lead end are combined into a single unit in a manner which greatly reduces the overall complexity of the device and allows a single power actuator to perform both functions.

Referring in particular to FIGS. 1 and 3, it will be seen that an elongated actuating member 46 is carried in'the lower portion of the drum (as viewed in FIGS. 1 and 3) and extends the length 'of the drum.. Member 46 comprises a relatively rigid metal bar which ismounted for radial reciprocation relative to the drum axis. The

cross-sectional configuration of the actuator bar is best shown in FIG. 3. Note that it has a first outer surface 48 that is contoured to form a continuation of the windingsurface defined by shell members 16 and 18. A pair of leg portions 50, 52 extend. upward from the main body of memberv 46 and define slide surfaces 54, 56, respectively. A suitable shaped opening 58 receives leg portion 50 and a similar opening 59 formed in the hub section 20 receives leg portion 56. Guide blocks 60, 62 are connected adjacent the recesses 58, 59 and form a guideway for the member 46. The guide blocks can-be connected to the hub in any convenient manner but are shown as releasably connected by socket screws 64, 66, respectively. Note that each of the guide blocks closely and slidably engages respective ones of the slide surfaces 54, 56.

Referring in particular to FIGS. 2 and 3, it will be noted that the member 46 has a second outer surface which is inclined and arranged to engage a'correspondingly inclined surface 72 formed on the lower free end of shell 18. When member 46 is moved outwardly, surface 70 acts to wedge or cam the segment radially outward about the shaft 32 (Le, counterclockwise as viewed in FIG. 2). When the member 46 is moved radially inwardto the position shown in FIG. 3, the segment 18 can move inwardly to the solid line position causing an effective contraction of the outer circumference of the winding drum.

As can be appreciated, positive movement of the segment 18 in a radial outward direction is assured by the movement of the member 46; however, to assure contractive movement, biasing means are provided to maintain the segment '18 under a continual bias in the radially inward direction. Means for accomplishing this could take many forms but, as best shown in FIGS. 1 and 2, the means utilized in the subject embodiment comprise a tension spring member connected between segments 16 and 18. As shown in FIG. 2, spring 80 is connected by studs 82 and 84, respectively. The outer-end of stud 82 is threaded and received in a flanged collar 86. Collar 86 is positioned in a counterbroed opening 88 formed in segment 16. The end of stud 84 is similarly threaded and received in a flanged collar 90 received in the counter-bored opening 92 formed in segment 18. Collars 86 and 90 are preferably provided with transverse slots so that a screwdriver or the like can be used for rotating the sleeves to vary the tension on spring 80. This arrangement assures that during inward retraction of the member 46, the drum segment 18 will be moved radially inward to produce the required drum collapse or contraction.

Many different types of power arrangements could be used for moving the member 48 radially outward at the desired times. According to the preferred embodiment, the subject device utilizes a highly simple and easily constructed hydraulic actuator arrangement which can best be seen in FIGS. 1 and 4. As shown, an elongated expansible hose member 94'extends substantially the length of the drum between the hub 20 and the member' 46. At'one end, the hose member 94 is folded over and connected to a plate 96 adjustably carried on the enlarged diameter portion 26 of center shaft 12 by a shoulder bolt 97 which passes through a slot in the plate and into theshaft. .As best shown in FIG. 1, the end of the hose is folded over at 98 and a short metal plate positioned thereover and connected by machine screws 100 which pass through the hose into plate 96. The other endof the hose is arranged as shown in FIG. 4 and is folded over and closed bya pair of plates 102 and 104 interconnected by socket screws 106 which pass through the hose and plate 102 into threaded engagement with plate 104.

FIG. 3 shows the hose 94 in its collapsed condition.

To expand the hose, means are provided for-supplying hydraulic fluid to its interior. As shown'in FIG. 4, the means comprise a threaded section of tubing 108 which is in fluid communication with the interior of the tube through a pair of plates 110 and 112. Plate 112 is positioned inside the hose and has a threaded bore 114 which receives the end of tube 108. The plate 110 is positioned exteriorly of the hose and several machine screws 116 pass through the plate 110 and hose 94 into tapped openings in plate 112. An angle plate or bracket 120 is connected to the end plate 28 by a socket screw 122. Plate 120 acts as a guide and inner stop for the outer end of the hose.

Hydraulic fluid is supplied to the tube 108 through a center bore 124 formed longitudinally of the center shaft assembly 12. A suitable rotary fltting'(not shown) connects the left-hand end of the bore 124 with a source of hydraulic fluid. The right-hand end of bore 124 is provided with an adaptor 126 which is connected through tubing 128, 130 and T-fltting 134 with the tube 108. A bleed or drain valve 132 is connected to the T-fitting 134.

As can be appreciated, expansion of the hose drives the member 48 outwardly causing the drum leaf or segment 18 to be expanded radially. Upon release of the hydraulic pressure within hose 94, the member 48 can move radially inward. To assure the required radial inward movement upon release of the pressure, biasing means are provided which maintain the member 46 under a continual inward bias.

Referring to FIGS. 1 and 2, the biasing means are shown as including a pair of tension springs positioned at the outer or right-hand end of the drum assembly and adjustably connected to the shells by assemblies and 142. Assembly 140 comprises a flanged sleeve 143 which is received in the counterbored opening 144 formed in sector 16. A threaded stud .145 extends outwardly of sleeve 143 and receives the upper end of a tension spring 146. The assembly 142 is identical in arrangement and comprises a flanged sleeve 148 received in a counter-bored opening 149 formed in the shell 18. The threaded stud 150 receives the end of tension spring 151. The lower ends of springs 146 and 151 are connected to a generally U-shaped plate 153 attached to the outer end of member 46 by a plurality of socket head machine screws 152. Accordingly, the member 146 is continually maintained under an upward bias and moves radially inward under the influence of the springs whenever the hydraulic pressure is relieved from within the hose 94.

The simplicity of the expansible drum thus far described is apparent. Note that only two moving machine parts are required to perform the expansion and contraction functions. Additionally, no special machining or complex hydraulic or mechanical actuators are required to produce the necessary movement. Further, all parts are arranged for ready disassembly for maintenance or repair.

As previously mentioned, when the drum is used as a rewind drum, means must be provided for gripping the lead end of the strip at the start of a winding operation. In the subject device, the gripping mechanism is interrelated with the expanding and contracting mechanism so as to produce further simplification in the overall drum structure. Referring in particular to Figures 1, 2 and 5, it will be seen that the left-hand portion of member 46 (as viewed in FIG. 3) has an elongated slot 155 formed the length thereof. Slot 155 receives gripper jaw segments 156 which are spaced uniformly along the length of the drum. Each of 'the gripper jaw segments are mounted for independent relative movement so that the assembly can grip strip which is of nonuniform thickness across its width. The segments 156 are preferably provided with a serrated inclined edge 157 adapted to cooperate with a correspondingly inclined surface formed on member 62. As mentioned, each of the gripper bars 156 are mounted for independent relative movement. As shown in FIG. 3, bars 156 are slidably received within the elongated groove 155. They are maintained therein by shoulder screws 157 which engage in suitable tapped openings formed in the bottom of the groove 155. Compression springs 158 are positioned about each of the screws 157 and maintain the jaws continually biased outwardly in the groove 155.

FIG. 3 shows the position of the jaws when the member 46 is in the radially contracted position. Note that a substantial space is present between the serrated edge 157 and the cooperating surface on member 62. This allows the lead end of a metal strip, for example, strip 160, to be inserted between the gripper jaw'segments and members 62. Thereafter, expansion of the drum and the outward movement of member 46 causes the serrated edge to engage the strip and clamp it firmly against members 62. The springs allow individual variations in the position of the segments to compensate for differences in thickness of the strip across its width.

Referring now to FIGS. 6 and 7, a modified form of actuating member and power arrangement is shown. The FIGS. 6 and 7 embodiment is substantially the same in all details as the FIGS. 1 through 5 embodiment. The primary differences reside in the mounting and actuating of the segment drive members. Accordingly, only this portion is shown in detail.

In particular, in this embodiment, the center shaft 200 is provided with a generally T'shaped groove 202 which extends along its lower surface. Positioned within the groove or T-slot 202 and arranged for reciprocation therein is a slide member 204. Member 204 is preferably made from a material such as brass or the like so as to have a good sliding coefficient of friction with the steel center shaft 200. Carried from the slide member 204 by a pair of pivot link assemblies 206 is the actuating member 208.

Broadly, actuating member 208 is of the same general construction asthe actuating member 46 of the FIGS. 1 through 5 embodiment. As shown, it has a lower surface 210 which defines a continuation of the winding surface formed by the two outer shells. Also, it has aninclined cam surface 209 which serves to actu- '7 ate the pivotal shell member. The actuating member 208 is slidably mounted for radial reciprocation in a groove or slot 210 formed in the sleeve or hub portion 212. As shown in FIG. 7, the actuating member 208 has a generally U-shaped cross-section and the two legs of the member extend upwardly and engage the side walls of the groove 210. In the left-hand leg (as viewed in FIG. 7), a strip clamp assembly 216 is arranged to cooperate with the left-hand shell for clamping the lead end of a strip. The clamp assembly 216 is identical in construction to the clamp assembly described in; detail with reference to the embodiment of FIGS. 1 through 5. Accordingly,.further description is not required.

Of importance to the subject embodiment is the arrangement used for causing selective radial reciprocation of the actuating member 208. As best shown in FIG. 6, the actuating member 208 is supported from the slide member-204 by the previously mentioned link assemblies 206. Member 208 is mounted so that it can have radial movement but is prevented from moving longitudinally of the shaft. This is accomplished by a transversely positioned slide or guide member 210 which extends downwardly from the center shaft 200. The guide member 210 extends into slots 220 formed in the left-hand ends of the leg portions of member 208 (as viewed in FIG. 6). As can be appreciated, member 210 allows the actuating member to move radially but prevents longitudinal movement. The link assemblies 206 comprise links 221 and 222 of standard, commercially available roller chain. The links are connected at their opposite ends to the slide member 204 and the actuating member 208. As best shown in FIG. 7, the upper ends of links 221 and 222 are respectively connected to elongated bars 223 and 224. The bars are welded to the rollers and releasably connected to the slide member 204 by socket head machine screws 226 (see FIG. 6). The lower ends of the links are similarly joined to elongated bars 227 and 228, respectively. Bars 227 and 228 are connected to thelactuating member 208 by screws 230 which-extend through counterbored openings formed through actuating member 208 intothreaded openings in the bar members. i

As can be appreciated, by reciprocating slide member 204 to the right, the actuating member is caused to move radially inward from the position shown in FIG. 6. Conversely, movement to the left causes the actuating member to be moved radially outward. The extent of outward movement can be varied by stop blocks or the like positioned in the T-groove 202. During movement of the actuating member, the pivotal shell is caused to move radially in the manner described with reference to the FIGS. l through embodiment.

Many different types of power means could be used for moving slide member 204; however, in the subject embodiment, the preferred means comprise a threaded shaft 232 carried in a support plate 234 which is connected tothe outer end of center shaft 200 by screws 236. The inner end of shaft 232 has a reduced diameter portion 238 which is rotatably received within opening 240 of a push block 242. Block 242 is joined to the right-hand end of slide member 204 in any convenient manner, such as by welding. It will be noted that a thrust bearing 244 is positioned between block 242 and shoulder 248 on shaft 232. The inner end of shaft 232 is provided with a snap ring 250 which maintains it releasably connected to block 242 while permitting it to rotate relative thereto. As can be appreciated, rotation of shaft 232-causes it to impart movement to slide member 204. The outer end ofshaft 232 is preferably provided with crank or tool receiving flats 249 so that it can be manually rotated.

The invention has been described in great detail sufficient to enable one of ordinary skill in the winding art to make and use the same. Obviously, ,modifications and alterations of the preferred embodiment will occur to others upon a reading and understanding of the spec ification and it is our intention to include all such modificationsand alterations as part of our invention insofar as they come within the scope of the appended claims.

What is claimed is: I 1. An expansible drum assembly for winding or unwinding strip material comprising:

a center shaft adapted to be cantileverly supported and carrying first and second arcuate outer shells which define all buta portion of the winding surface andextend throughout a substantial portion of the lengthof the shaft; each of the shells having a circumferential extent of less than said first shell being rigidly affixed to said shaft and second shell being pivotally connected to the structure defined by the first shell and the shaft about an axis adjacent to one of the longitudinal edges of the second shell; biasingmeans for maintaining the second shell continuously biased in an inward direction; actuating means comprising an elongated actuating member between said shells and mounted for radial sliding movement, said actuating member having a first surface which forms said portion of .the winding surface and a second surface which engages the free end portion of the second shell; and, drive means for selectively moving the member radially outward to cause the second shell to move outwardly against .the biasing means to expand the shell. 2. The assembly as defined in claim 1 wherein said actuating member is carried by pivot link assemblies.

3. The assembly as defined in claim 1 wherein said drive meansincludesan expansible hose member positioned between said actuating member and said shaft.

4. The assembly as defined in claim 1 including strip gripping means, said gripping means including a first gripping jaw carried on said actuating member and a second gripping jaw carried by th e first shell and located so that during outward movement of the actuating member, the jaws engage.

5. The assembly as defined in claim 4 wherein at least one of the gripping jaws comprises a series of separate- 3,815,839 9 8. The assembly as defined in claim 1 wherein said drive means comprise an expansible member posiactuating member is carried from said shaft by a slide tioned between said shaft and said actuating member. member mounted for longitudinal movement.

9. The assembly as defined in claim 8 wherein pivot 11. The assembly as defined in claim 10 wherein said links connect said actuating memberto said slide mem- 5 expansible member comprises a hose extending longiber. tudinally of said shaft.

10. The assembly as defined in claim 1 wherein said 

1. An expansible drum assembly for winding or unwinding strip material comprising: a center shaft adapted to be cantileverly supported and carrying first and second arcuate outer shells which define all but a portion of the winding surface and extend throughout a substantial portion of the length of the shaft; each of the shells having a circumferential extent of less than 180*; said first shell being rigidly affixed to said shaft and second shell being pivotally connected to the structure defined by the first shell and the shaft about an axis adjacent to one of the longitudinal edges of the second shell; biasing means for maintaining the second shell continuously biased in an inward direction; actuating means comprising an elongated actuating member between said shells and mounted for radial sliding movement, said actuating member having a first surface which forms said portion of the winding surface and a second surface which engages the free end portion of the second shell; and, drive means for selectively moving the member radially outward to cause the second shell to move outwardly against the biasing means to expand the shell.
 2. The assembly as defined in claim 1 wherein said actuating member is carried by pivot link assemblies.
 3. The assembly as defined in claim 1 wherein said drive means includes an expansible hose member positioned between said actuating member and said shaft.
 4. The assembly as defined in claim 1 including strip gripping means, said gripping means including a first gripping jaw carried oN said actuating member and a second gripping jaw carried by the first shell and located so that during outward movement of the actuating member, the jaws engage.
 5. The assembly as defined in claim 4 wherein at least one of the gripping jaws comprises a series of separate sections, each of said sections being independently biased toward the other gripping jaw.
 6. The assembly as defined in claim 1 wherein said second shell has a cam surface formed along its free edge and wherein said actuating member is positioned to engage said cam surface upon outward radial movement.
 7. The assembly as defined in claim 1 wherein said drive means comprise a member adapted to be moved longitudinally to impart radial movement to said actuating member.
 8. The assembly as defined in claim 1 wherein said actuating member is carried from said shaft by a slide member mounted for longitudinal movement.
 9. The assembly as defined in claim 8 wherein pivot links connect said actuating member to said slide member.
 10. The assembly as defined in claim 1 wherein said drive means comprise an expansible member positioned between said shaft and said actuating member.
 11. The assembly as defined in claim 10 wherein said expansible member comprises a hose extending longitudinally of said shaft. 